I seem to recall reading somewhere that any money put into the DC 529 must stay there for 2 years before being rolled out, if you want to avoid the tax penalty. So for example, if you put in money on 1/1/15, you can roll it out on 1/1/17. If you wait until 6/1/16 to contribute, that money must stay until 6/1/18. Makes sense I suppose.
DC's investment options and charges are really terrible. I emailed them a while ago to complain, and they responded that they're planning to renegotiate fees with the investment firm this summer. Please write to encourage them to switch to Vanguard or some other low-cost provider.